This invention relates to devices for terminating electromagnetic interference (hereinafter EMI) shielded wiring and more particularly to heat-recoverable shield connection devices for terminating shielded wiring which include their own EMI shielding.
In many military and civilian applications, it is very desirable to have cable, harnesses or the like wiring which include either individually EMI shielded conductors or gross EMI shielded conductors and in some instances both individually and gross shielded conductors. It is necessary to terminate the cable's shielding for connection to control panels, P.C. boards or for connection with other wiring and the like. It is desirable to maintain EMI shielding from the device's shield termination point up to and including the connection point.
Conventional EMI shielding is a metallic braid which often proves difficult to work with at connection points because the braid filaments often fray. Conventional methods of tying off the braid include stripping back the cable's braid a few inches behind the connection point and, thereby leaving the insulated conductors unshielded a few inches behind the connection point. This exposure to possible EMI of insulated conductors greatly reduces the overall beneficial effects of the cable's EMI shielding. To avoid this possible EMI exposure, there should be 360.degree. of EMI shielding from where the braid is tied off (the termination point) up to and including the connection point. Rigid tubular connection devices having EMI shielding may be used to solve the problem but many applications, e.g. back shell connections, require flexible EMI shielding. Conventional braid has proven satisfactory for flexible applications. In fact, De Groef et al U.S. Pat. No. 4,144,404 and Gozlan U.S. Pat. No. 4,246,438 disclose the use of such braid for coaxial cable connections. A desirable shield and a means for preventing fraying of the shield.
As will be appreciated the terminated end of the cable's braid is quite delicate and frays quite easily. If one terminates the cable's braid and inserts it into either of the above cited references, fraying and damage will generally result to the cable's and device's EMI shielding. The damage to the device's shield may cause gaps in the EMI shielding for the cable resulting in poor overall EMI shielding efficiency. Inserting the cable's EMI braid into known termination devices must be done carefully and gently in order not to damage the device's shield. This required care results in greatly increased labor costs for providing good overall EMI protection.
The device of the instant invention provides an inside guide means which facilitates a fast, labor efficient method of inserting the terminated end of a cable's braid into a connection device. Additionally, the device of the instant invention provides an inside guide means for preventing damage to the cable's braid and promoting overall EMI shielding protection. Additionally, the device of the instant invention provides its own EMI shielding which defines a 360.degree. EMI gross shield for EMI shielding from the cable's shield termination point to the connection point.